Propeller



Jan. 18, 1927. 1,614,872

J. J. CALLAHAN I PROPELLER Filgd Apgust 6 1925 2 Sheets-Sheet l v JOGEPH d Cam/#1 Patented Jan. 18, 1927.

JOSEPH J. CALLAHAN, OF CORNWELLS HEIGHTS, PENNSYLVANIA.

PROPELLER.

Application filed August 6, 1925.

This invention relates to propellers and more particularly to a propeller having a combined screw and compressor blade.

An important object of the invention is to provide a propeller having an inclined blade adapted to act as a screw for forcing fluid outwardly of the propeller rearwardly thereof, and to provide a compressor blade portion arranged substantially at right angles to the plane of rotation to create a pressure in the fluid within the propeller pocket to increase the propelling efficiency.

A further object is to provide a propeller of the above mentioned character wherein each blade is curved forwardly adjacent the hub and rearwardly adjacent its outer end, each blade as a whole being also curved in the direction of its rotation to set up a centripetal force adapted to balance the normal centrifugal force to prevent radial slipping of the fluid whereby the latter will be projected rearwardly of the propeller to exert an eflicient propelling force.

A still further object of the invention is the provision of a propeller curved longitudinally in the manner above described to produce a movement of the fluid toward the center or axis and equalize the pressure.

A still further object is to provide a propeller of the above mentioned character wherein the fluid ejected by the propeller rearwardly thereof will assume a shape approximating a cylinder the linear speed of which will be substantially equal throughout.

A still further object is to provide a propeller having a blade including a screw surface and a compressor surface joined substantially at an angle to each other, the blade being provided on its opposite side with a substantially continuous inclined screw surface to permit the propeller to be reversed for reversing the action of the vessel to which the propeller is attached.

A still further object is to provide a propeller provided with a hub extending forwardly of the blades, each of the latter being provided with screw and compressor portions which extend inwardly to the center line of the hub rearwardly thereof, the compressor portions of the blades intersecting in a line coincident with the axis of the hub whereby the entire diameter of the propeller is effectually employed as propelling means.

Other objects and advantages of the in- Serial No. 48,665.

vention will be apparent during the course of the following description.

In the drawings, I have shown several embodiments of the invention. In this showing:

Figure 1 is a side elevation of one form of propeller,

Figure 2 is a front elevation of the same,

Figure 3 is a rear elevation,

Figure 4 is a section on line 44 of F igure 1,

Figure 5 is a similar view on line 55 of Figure 1, and

Figure 6 is a perspective View of a somewhat modified form of propeller.

Referring to the drawings the numeral 10 designates the hub of the propeller provided with a slot 11 internally thereof whereby the hub may be keyed to a suitable propeller shaft as will be obvious. A plurality of blades 11 are preferably cast integral with the hub and project outwardly therefrom, as shown. In the present instance I have shown the propeller as being provided with two blades but it will be obvious that any suitable number may be employed.

Each of the blades comprises a screw sur face 12, inclined as shown in Figures 4 and 5, and a compressor surface 13 arranged substantially at right angles to the plane of rotation. The blade as a whole is inclined forwardly at its inner portion, and thence curves rearwardly toward its outer end, as clearly shown in Figure 1. The widest portion of the screw surface occurs substantially at the point 14 intermediate the ends of the blade, and at this point it will be apparent that the blade projects the greatest distance into the fluid medium in which it operates. From the intermediate point 14, each of the screw surfaces decreases in width toward its outer end. The compressor surface 13 of each of the blades gradually increases in width from the extremity of the blade to the center of the hub as shown in Figure 1.

In the formation of the propeller described, I prefer to arrange the hub 10 forwardly of the inner portions of the blade as shown in Figure 1 whereby the latter may extend inwardly to the center line of the hub as shown in Figure 3. In this figure of the drawfngs it will be apparent that each of the screw surfaces extends inwardly against a shoulder 15 formed on the inner end of the adjacent blade. The shoulders 15, of course, will lie in a plane coincident with the axis of the hub. Each of the compressor faces 13 also extends inwardly to the center line of the hub, and these faces have their inner ends arranged in alinement to each other and intersect the faces of the shoulders 15 in a line 16 which is coincident with the axis of the hub, as will be apparent. It will'be obvious, therefore, that the effective propelling surfaces of the blades extendthroughout the entire diameter of the blades. I

Opposite the screw and compressor faces of each of the blades, a continuous screw surface 17 is provided as shown in Figures 2 and 4. These faces are inclined withrespect to the plane of rotation and are adapted to project fluid forwardly when the propeller is reversed. Obviously the curvature of the faces 17 will be reversed with respect to the faces 12 and 13, but sufiicient screw action will be set up to permit the vessel to which the device is attached, to be reversed in its direction of travel.

In Figure 6 I have shown a somewhat modified form of propeller wherein the same general elements are employed, and these elements need not be described in detail. In this form of the propeller the hub is extended to the opposite side of the propeller, as shown at 18. This form of the propeller is particularly adapted for use in connection with aeroplanes wherein the propeller is driven from a power source arranged rearwardly thereof.

The operationof the device is as follows:

The propeller will be rotated in a clockwise direction as viewed in Figure 3 and in a counterclockwise direction as viewed in Figure 2. The screw faces 12 will operate in the usual manner to project fluid rearwardly as will be understood. The provision of the compressor faces serves to effect a compression of the fluid in the pockets formed between the screw and compressor faces to more efliciently eject the fluid rearwardly of the propeller and prevent the slippage of fluid from the rear side of each blade as it rotates. As previously stated the compressor face of each blade increases in width gradually toward its center and this increase in width is adapted to compensate for the slower linear speeds toward the center of the propeller so that the pressure tends to equalize. As also previously stated, each of. the screw faces is widest substantially at the point lawhereby each of the blades projects a greater distance forwardly at this point. Thus a greater portion of the fluid will beintercepted by the blades at the points 14 and this fluid tends to spread toward the inner and outer ends of the blade. The tendency to spread toward the outer ends of the blades is overcome by the curva ture of the blades in the direction of their rotation to create a centripetal force which not only equalizes the tendency of the fluid to spread in opposite directions from the points letbut also overcomes the normal centrifugal action created. In this manner it has been found that substantially equal pressure can be created throughout the length of each blade so that the fluid is projected rearwardly at a substantially equal velocity throughout the length of each blade. The neutralization of the centrifugal force also causes the ejection of a substantially cylindrical column of fluid whereby a force is created in a line directly opposite to the direction of motion as is desired. The provision of blades which extend inwardly to the center line of the hub, as shown in Figures 1 to 5 inclusive, creates a solid column of water which will be unbroken at its center whereby the efficiency of the propeller is gradually increased.

The forward curvature of the portion of the blade adjacent the hub and the rearward curvature of the portion of the blade adjacent the outer end produces a movement of. the fluid toward the center, thus equalizing the pressure, This puts greater pressure on the flange and gives an equal pressure to that part of the blade that is rearward of the hub.

The operation of the form of the device shown in Figure 6 is substantially the same as that previously described except that the effective portions of the blades do not extend wholly to the center of the hub. This form of the propeller'acts in the same manner as that previously described, however, in that it neutralizes centrifugal force by creating a counter centripetal force whereby the fluid will be ejected in lines parallel to and opposite to the direction of movement This form of the device is particular-- ly adapted for use as a driving means for aeroplanes and the like wherein the motive power employed is arranged rearwardly of the propeller. The form of the device illustrated in Figures 1 to 5 inclusive is par ticularly adapted for propelling ships where power is delivered to the propeller from a point forwardly thereof.

It is to be understood that the forms of my invention herewith shown and described are to be taken as preferred examples of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit or the invention or the scope of the suboined claims.

I claim:

1. A propeller comprising a hub, and a blade extending outwardly therefrom, said blade having a screw face arranged at an acute angle to the plane of rotation and a compressor face intersecting sa'id screw face and arranged substantially at right angles to the plane of rotation, said faces being curved in the direction of rotation, said compressor face increasing in width toward its inner end.

2. A propeller comprising a hub, and a blade extending outwardly therefrom, said blade having a screw face arranged at an acute angle to the plane of rotation and a compressor face intersecting said screw face and arranged substantially at right angles to the plane of rotation, said faces being curved in the direction of rotation, said screw fa'ce having its inner and outer portions extending rearwardly from a point intermediate its ends.

3. A propeller comprising a hub, and a blade extending outwardly therefrom and curved in the direction of its rotation, said blade having a screw face arranged at an acute angle to the plane of rotation and a compressor face intersecting said screw face and arranged substantially at right angles to the plane of'rotation, said compressor face increasing in width toward its inner end, said blade having its inner and outer portions extending rearwardly from a point intermediate its ends.

4. A propeller comprising a hub, and a blade extending outwardly therefrom, said blade having on one side a screw face, and a compressor face intersecting said screw face and arranged substantially at right angles to the plane of rotation, said blade being provided on its opposite side with a continuous screw face pitched in the same direction as said first named screw face.

5. A propeller comprising a hub, and a blade extending outwardly therefrom, said blade having on One side a screw face, and a compressor face intersecting said screw face and arranged substantially at right angles to the plane of rotation, said blade being provided on its opposite side with a continuous screw face pitched in the same direction as said first named screw face, said blade being curved substantially throughout its length in the direction of rotation and extending rearwardly toward its ends from a point intermediate its ends, said screw face being widest at said intermediate point.

6. A propeller comprising a hub, a pair of blades arranged rearwardly of said hub and extending outwardly therefrom on opposite sides thereof, each of said blades having a screw face and a compressor face intersecting said screw face and arranged substantially at right angles to the plane of rotation, said compressor faces having their inner ends arranged substantially in alinement with each other and meeting in a line coincident with the axis of said hub, said blades being curved in the direction of rotation and each extending rearwardly toward its ends from a point intermediate its ends.

7. A propeller comprising a hub, a pair of blades arranged rearwardly of said hub and extending outwardly therefrom on opposite sides thereof, each of said blades having a screw face and a compressor face intersecting said screw face and arranged substantially at right angles to the plane of rotation, said compressor faces having their inner ends arranged substantially in alinement with each other and meeting in a line coincident with the axis of said huh, said blades being curved in the direction of rotation and each extending rearwardly toward its ends from a point intermediate its ends, each of said screw .faces being widest at said intermediate point, each of said compressor faces increasing in width toward its inner end.

S. A propeller comprising a hub, and a blade extending outwardly therefrom, said blade having a screw face arranged at an acute angle to the plane of rotation, and a compressor face intersecting said screw face and arranged substantially at right angles to the plane of rotation, said faces being curved in the direction of rotation.

9. A propeller comprising a hub and a blade extending outwardly therefrom, said blade having on one side a screw face, and a compressor face intersecting said screw face and arranged substantially at right angles to the plane of rotation, said blade being provided on its opposite side with a continuous screw face pitched in the same direction as said first named screw face, said blade being curved substantially throughout its length in the direction of rotation.

10. A propeller comprising a hub, and a blade extending outwardly therefrom, said blade having a screw face arranged at an acute angle to the plane of rotation, and a compressor face intersecting said screw face and arranged substantially at right angles to the plane of rotation, said blade being provided on its opposite side with a continuous screw face pitched substantially in the same direction as said first named screw face, said blade being curved in the direction of rotation, said blade being further bent or curved away from the longitudinal direct-ion of travel.

11. A propeller comprising a hub, and a blade extendingoutwardly therefrom, and curved in the direction of its rotation, said blade having a screw face arranged at an acute angle to the plane of rotation, and a compressor face intersecting said screw face and arranged substantially at right angles to the plane of rotation, said compressor face increasing in width towards its inner end, said blade being bent or curved away from the longitudinal direction of travel, said blade being also provided on its opposite sicle with a continuous screw face pitched substantially as the first named screw face.

7 tending outwardly therefrom, each of said blades having a screw face, and a compressor face intersecting said screw face and arranged substantially at right angles to the plane of rotation, said compressor faces having their inner ends extending behind the hub toward its center, saidblades being curved in the direction of rotation, and extending away from the longitudinal direction of travel.

13. A propeller comprising a hub, blades arranged rearwardly of said hub and extending outwardly therefrom, each-0f said blades having a screw face, and a compressor face intersecting said screw face and arranged substantially at right angles to the plane of rotation, said compressor faces having their inner ends extending behind the hub toward its center, said blades being curved in the direction of rotation, and extending away from the longitudinal direction of travel, each of said compressor faces increasing in width toward its inner end.

In testimony whereof I affix my signature.

JOSEPH J.v CALLAHAN. 

